In internal combustion engines, in particular in gasoline-operated motor vehicle engines, camshafts are used to actuate what are known as the gas exchange valves. The cams of the camshafts usually bear against cam followers, for example cup tappets, finger levers or rocker arms. If a camshaft is set in rotation, the cams roll on the cam followers which in turn actuate the gas exchange valves. Both the opening duration and the opening amplitude, but also the opening and closing times of the gas exchange valves, are fixed by the position and the shape of the cams.
The angular displacement of the camshaft in relation to a crankshaft in order to achieve optimized control times for various rotational speed and load states is called camshaft adjustment. For example, one structural variant of a camshaft adjuster operates according to what is known as the pivoting rotor principle. Here, a stator and a rotor are provided which lie coaxially and can be moved relative to one another. The stator and the rotor together form hydraulic or pressure chambers. Here, a chamber pair is delimited in each case by webs of the stator and is divided by a respective vane of the rotor into two chambers which run in opposite directions with respect to one another and the volumes of which are changed in opposite directions by a relative rotational movement of the rotor with respect to the stator. In the maximum adjustment position, the respective vane bears against one of the edge-side webs of the stator. The relative rotational movement of the rotor takes place by way of an adjustment of the vane, by a hydraulic medium, such as oil, being introduced into the chambers via radial ducts and pressing the vane away. By way of the adjustment of the rotor, the camshaft which is fastened to the rotor is adjusted, for example, in the early direction, that is to say an earlier opening time of the gas exchange valves. By way of adjustment of the rotor in the opposite direction, the camshaft is adjusted with respect to the crankshaft in the late direction, that is to say a later opening time of the gas exchange valves. Here, the hydraulic medium is introduced into the radial passages, for example, via a central oil feed which is formed by a central bore for receiving a central screw for fastening the rotor to the camshaft. One such prior art arrangement from US2010/0089349 is shown in FIG. 3, which shows the rotor and stator.
The connection between the rotor and the camshaft is as a rule nonpositive and takes place via the central screw. However, it is a disadvantage of this embodiment that a high tightening torque of the screw is required. In addition, relatively little space is available in the region of the screw head of the central screw, with the result that the access to the screw head is made difficult, which makes the tightening of the central screw more problematic.